I have the same board. Just bought it yesterday with a Phenom II X6 and 8gb of Corsair XMS3 1333 DDR3 - 4 2gb chips. I can't get my system to boot without a beep code unless I put one dimm in slot 4 and that's it. I updated to the F6 BIOS and I really don't want to update to the F7B Beta bios. Any advise on the matter would be helpful.